Antidepressants and Weight Gain: What You Need To Know

Will taking an antidepressant make me gain weight? That’s a question heard daily by psychiatric pharmacist Josh Maline, PharmD, BCPP — and the answer isn’t a clear-cut “yes” or “no.”

“Weight changes can happen when people start taking antidepressants, but it’s not the case for everyone,” says Dr. Maline. “It depends on a number of different factors.”

So, let’s take a closer look.

Do antidepressants cause weight gain?

Weight gain is a common potential side effect of taking antidepressants. A 2024 study shows that increases are typically minor, averaging about 3 pounds within two years of starting a medication.

“But I’ve talked with patients who have gained significantly more weight on antidepressant medication, too,” Dr. Maline notes. “It truly does vary person to person.”

Unless your weight increase is quick and dramatic (like putting on 5-plus pounds within a week), Dr. Maline recommends not being preoccupied with slightly higher numbers that might appear on your scale.

“Try to focus on how you’re feeling and if the medication is helping address your symptoms of depression or anxiety,” he recommends. “Weight is not something to overly fixate on.”

But if a weight change is causing you concern, talk to your healthcare provider. “Do not just stop taking your medication or make changes to it,” he urges. “There are options that can be considered.”

Why taking antidepressants might cause weight gain

There’s no single answer to why someone might gain weight after starting antidepressants.

The medication itself may play a role, as research shows some antidepressants are more associated with weight increase than others, explains Dr. Maline. But other factors could drive the change, too.

Antidepressants that may cause weight gain

The previously mentioned study on antidepressants and weight change looked at common first-line treatment medications. It used the most commonly prescribed antidepressant — sertraline (Zoloft®) — as a baseline.

On average, people who took Zoloft gained 3.2 pounds in 24 months. Numbers were similar for people taking fluoxetine (Prozac®). Both are types of SSRIs (selective serotonin reuptake inhibitors).

Average weight gain and chances of more excessive weight gain were higher for those taking SSRIs such as:

• Escitalopram (Lexapro®)
• Paroxetine (Paxil®)

More weight gain was also seen in those taking:

• Duloxetine (Cymbalta®), an SNRI (serotonin and norepinephrine reuptake inhibitor)

Going in the opposite direction, weight gain was lower for those taking:

• Bupropion (Wellbutrin®), which is an NDRI (norepinephrine and dopamine reuptake inhibitor)

But again, Dr. Maline emphasizes that results can vary person to person. Medication that adds pounds for one individual may not do so for someone else.

Other factors that might cause weight gain

Mental health conditions often affect appetite. “If you’re depressed or anxious, it can change your eating patterns — and that can result in weight loss or gain, depending on how you respond,” explains Dr. Maline.

If your weight is low before you begin treatment, the weight gain that comes with taking an antidepressant may simply be an indicator of improved appetite.

“You may gain weight just by returning to a more typical eating pattern with your improved mood,” he continues. “In a way, it can be a sign that the treatment is working and you’re feeling better.”

It should also be noted that some weight gain is typical as people age, so any changes you see may just be the toll of time.

How to prevent weight gain while taking antidepressants

The same rules for weight management apply to those taking antidepressants and those who aren’t. “Eat a healthier diet, start an exercise routine, take steps to reduce stress and get enough sleep,” advises Dr. Maline.

You may find it easier to adopt lifestyle changes as your emotional state improves while taking an antidepressant. You may feel more energized and up for new challenges.

Again, too, talk to your healthcare provider if you experience rapid or significant weight gain. They may adjust your prescription or suggest trying a different medication to treat your symptoms.

“The ultimate goal is to find a balance where both mental and physical health are supported,” says Dr. Maline.